SJ 
i) 
1. Erythrocladia irregularis sp. nov. 
Thallus minutus, ambitu irregulari. Fila lateraliter ramosa, irregulariter ra- 
diantia, sæpe maxima pro parte inter se discreta. Rami plerumque in cellula sub- 
terminali nascuntur. Cellule plerumque oblongæ, long. 7—11 y, lat. 3,5 —5 y, 
chromatophorum unicum parietale, ut videtur pyrenoide instructum, continentes. 
Sporangia diametro c. 4 y. 
Scumitz has established a genus Erythropeltis (1896 p. 313), which in its re- 
production agrees with the genus Erythrotrichia but differs from it by the frond 
consisting only of a monostromatic disc with continuous border and with marginal 
growth. To this genus is only referred one species, E. discigera (Berth.) Schmitz!, 
and to the same species BATTERS has later referred a new variety, var. Flustre, 
(Journ. of Botany, Vol. 38, 1900 p. 376). The thallus is described in this as “orbi- 
cular, becoming confluent and irregular in outline’, and it must therefore be supposed 
that the irregularity only appears by the fusion of originally separate discs. In our 
plant, on the contrary, the frond consists of mutually separate filaments which only at 
a later stage are partly confluent, and it must therefore be referred to a new genus. 
The plant of which a diagnosis is given above was found in rather great, 
numbers on some specimens of Polysiphonia urceolata dredged off Hirshals in the 
Skagerak. It forms irregular spots of up to 100 » in diameter on the surface of 
the host-plant. It consists at first of branched filaments whose branches are mutu- 
ally enlirely separate. As shown in fig. 11 A the primary filament grows out in 
two opposite directions and gives off branches at both sides. These branches grow 
out and branch further, and in the more developed plant the filaments are there- 
fore radiating in all directions in the horizontal plane, and the filaments are then 
more or less fused together in the central part of the frond. The filaments show 
apical growth, and transverse walls appear only in the terminal cells, a natural 
consequence of the filaments being fixed to the substratum. The branches usually 
arise in the subterminal cell, sometimes also in cells nearer the centre of the frond, 
but the terminal cell is only very seldom ramified. The ramification is thus 
strongly monopodial. Not seldom a number of consecutive cells each give off a 
branch, now alternating, now secund. The outline of the plant is always more or 
less irregular, some filaments growing longer than others. 
The cells contain a single chromatophore, the form and structure of which I 
have not been able to determine with certainty, as I have only had dried speci- 
mens at my disposal. In several cases however it appeared to be undoubtedly 
parietal, and I often saw a body which I took to be a pyrenoid, though it was not 
very distinct (fig. 12). 
from a cell in the continuity of the branched filaments recall the genus Erythrocladia, but the plants 
need further examination. None of the described species can apparently be referred to the genus 
Erythrocladia. 
7 The genus is founded on Erythrotrichia discigera Berth.; but, according to BERTHOLD (1882 p. 25), 
the dise in this species sometimes produces erect filaments, and it must therefore be supposed that 
Scumirz has taken the species in a more restricted sense than BERTHOLD. 
